package usecase

import (
	"context"
	"fmt"
	"log/slog"

	"github.com/paramah/gw_telegram/internal/application/dto"
	"github.com/paramah/gw_telegram/internal/domain/port"
)

type HandleVoiceMessage struct {
	downloader  port.FileDownloader
	converter   AudioConverter
	transcriber port.SpeechTranscriber
	textHandler *HandleTextMessage
	gateway     port.MessageGateway
	logger      *slog.Logger
}

// AudioConverter converts audio between formats (OGG -> WAV etc.)
type AudioConverter interface {
	Convert(ctx context.Context, input []byte, fromMime, toMime string) ([]byte, error)
}

func NewHandleVoiceMessage(
	downloader port.FileDownloader,
	converter AudioConverter,
	transcriber port.SpeechTranscriber,
	textHandler *HandleTextMessage,
	gateway port.MessageGateway,
	logger *slog.Logger,
) *HandleVoiceMessage {
	return &HandleVoiceMessage{
		downloader:  downloader,
		converter:   converter,
		transcriber: transcriber,
		textHandler: textHandler,
		gateway:     gateway,
		logger:      logger,
	}
}

func (h *HandleVoiceMessage) Execute(ctx context.Context, in dto.IncomingMessageDTO) error {
	_ = h.gateway.SendTyping(ctx, in.ChatID)

	audioBytes, mimeType, err := h.downloader.Download(ctx, in.VoiceFileID)
	if err != nil {
		h.logger.ErrorContext(ctx, "voice download failed", "error", err, "file_id", in.VoiceFileID)
		_ = h.gateway.SendText(ctx, in.ChatID, "Sorry, I couldn't download the audio message. Please try again.")
		return fmt.Errorf("handle voice: download: %w", err)
	}

	// Convert OGG Opus (Telegram default) to WAV for Whisper
	if mimeType == "audio/ogg" || mimeType == "" {
		wavBytes, err := h.converter.Convert(ctx, audioBytes, "audio/ogg", "audio/wav")
		if err != nil {
			h.logger.WarnContext(ctx, "audio conversion failed, trying raw", "error", err)
			// fall through with original bytes
		} else {
			audioBytes = wavBytes
			mimeType = "audio/wav"
		}
	}

	transcript, err := h.transcriber.Transcribe(ctx, audioBytes, mimeType)
	if err != nil {
		h.logger.ErrorContext(ctx, "transcription failed", "error", err)
		_ = h.gateway.SendText(ctx, in.ChatID, "Sorry, I couldn't understand the voice message. Please try sending text instead.")
		return fmt.Errorf("handle voice: transcribe: %w", err)
	}

	h.logger.InfoContext(ctx, "voice transcribed", "user_id", in.UserID, "length", len(transcript))

	textIn := in
	textIn.Text = transcript
	textIn.IsVoice = false

	return h.textHandler.Execute(ctx, textIn)
}